The present invention relates to culvert structures and, more particularly, to low headroom culvert structures made up of a series of shallow arch-shaped corrugated sections reinforced and secured together in an improved fashion to form an elongated culvert.
In the past, low headroom, drainage and flood control culverts, etc., were made up of appropriate shallow arch sections and required full reinforcing floors or bottom sections to prevent culvert section failure during installation and use because of the shallow arch configuration, even when the culvert sections were stiffened by corrugations. This full flooring was secured to the opposing free bottom edges of the culvert arches and by tieing these ends or edges together transformed the culvert into a box-like shape and prevented the arched sections from spreading out and collapsing under loads. The flooring served an additional function in that it helped to nullify or minimize erosion of the soil between and adjacent the arch frames which, over a period of time, could otherwise produce the partial or total collapse of the culvert and require its ultimate removal and replacement. The use of such full flooring, however, materially increased the amount of material used and, in turn, the cost to the user. Examples of such prior art floored and corrugated culvert structures are shown in U.S. Pat. Nos. 950,928; 1,013,440; 1,040,442; 1,071,185; 1,926,843; 1,935,273; and 2,343,029.
Certain other prior art culverts, some of box-shape and low arch configuration, were also provided with internal or external footings, antiwash aprons, etc., some of simple and others of complex construction for the purpose of anchoring the culverts in place and minimizing soil erosion and displacement of the culvert sections. Examples of culverts provided with such footings, etc., are illustrated in U.S. Pat. Nos. 1,928,480; 1,955,407; 1,964,313; 2,126,091; 2,126,870; and 2,343,029. When these footings, etc., were utilized, however, they also required additional materials as well as special on-site installation preparations and procedures all of which added to the cost of the final culvert.
The proposed culvert structure constitutes an improvement over the prior art culvert structures as represented, for example, by the aforementioned prior art patents as well as an improvement over typical structural metal plate drainage systems including box-like culverts as illustrated in various brochures distributed by Kaiser Aluminum & Chemical Sales, Inc., Oakland, California, such as a brochure entitled "Aluminum Structural Plate" printed in 1965; a brochure entitled "Aluminum Structural Plate" copyrighted in 1974; and a brochure entitled "Aluminum Storm Sewers" copyrighted in 1976. Finally, the instant culvert is an improvement over the culvert structure of U.S. Pat. No. 3,508,406 which uses concrete beams secured to the outside of the culvert sections to reinforce the culvert and the trussed culvert of U.S. Pat. No. 1,999,500.
The instant low headroom culvert design advantageously minimizes the number of parts employed in the culvert structure while possessing substantially equivalent strength characteristics to those possessed by the low headroom culvert structures of the past which employed full bottom tie sections.